Q: Trust Alert absence.

Hi

The question asking whether you wish to trust the computer is shown when you connect your iPhone to the computer for the first time.

If you choose to trust the computer, it is normal for your iPhone to remember that computer and for the question not to be asked again. If you instead choose not to trust it, the question will be asked again when the iPhone is next connected.

If the Trust alert does not appear, try the following steps:

• On your iMac: check that you have installed the latest version of iTunes:
  • Get the latest version of iTunes - Apple Support
• Disconnect and reconnect your iPhone.
• Restart your iPhone and your iMac.
• Reset your Trust settings:
  • On your iPhone, go to: Settings > General > Reset > Reset Location & Privacy.
• Reset your network settings:
  • On your iPhone go to: Settings > General > Reset > Reset Network Settings;
  • Note that you will need to re-enter Wi-Fi credentials (cellular, VPN and APN settings are also reset).

Given the steps that you have already tried, I suggest that you contact Apple Support or make a Genius Bar reservation for assistance:

• Contact - Official Apple Support
• https://twitter.com/applesupport
• http://www.apple.com/retail/geniusbar/

On your Mac, open iTunes > Preferences > Advanced > click on Reset Warnings.

Hi,

Check out the information in this support article >  About the 'Trust This Computer' alert on your iPhone, iPad, or iPod touch - Apple Support